SEARCH KEYWORD -- OBJECT


  The danger of target=_blank and opener

When want to open a new page in a new tab on clicking a link on a page, the usual way of achieving this is to use target="_blank" property in a tag. However, the use of this leaves space for phishing website. Background parent and opener Before talking about the opener object, let's know a bit about parent object when using iframe. HTML provides a parent object which is used to communicate between the parent page and the embedded iframe element. This parent object can be accessed using...

   HTML,TARGET BLANK,REL NOOPENER,REL NOREFERRER     2018-09-15 04:53:56

  Let's talk about JSON.stringify()

JSON has been used in lots of places to exchange data among different services/systems. Nowadays all mainstream programming languages have built-in library support of JSON data parse and stringify. In this post, let's talk about JSON.stringify() in JavaScript. Let's first take a small example of Object conversion handling. There is a requirement to convert below object const todayILearn = { _id: 1, content: '今天学习 JSON.stringify()，我很开心！', ...

   JAVASCIPT,JSON,JSON.STRINGIFY     2020-02-22 04:25:08

  Bug caused by using changeable value as the default in "python method overload"​

In python we can set the passed in parameter's default value to make the function has the same running feature as the method overload in Java. Define a function like this: def testFunction(self, param1, param2=None, param3=None): Normally we use "None" as the parameter's default value. We can also use str/bool as the default value, but is it OK we use empty list [] as its default value? This is our test program: """ A test program using empty list as the passed-in parameter's default value. ...

   PYTHON     2019-03-11 08:52:52

  Check file readability in Java

File operation is quite platform dependent. Although Java is a cross platform programming language, the file operation in Java is also platform dependent. The obvious evidence is the file permission check. In Java, we can call canRead(), canWrite() and canExecutable() to check whether the program can read, write or execute the file specified. However, on Windows, when we call canRead() on a File object, we may get unexpected result. Actually, on Windows, when we call canRead() on a File object, ...

   Java,Files,Readable,Check     2013-12-05 06:10:15

  How to write your own DSL in Ruby

DSL(Domain Specific Language) is a language defined to fulfill some domain specific requirements to ease people's work. It can be used to define attributes and actions of a domain easily and cleanly. And it is often created based on some common observations or micro patterns of some domain. In Ruby world, there are quite a few places people can find DSL. For example, Ruby itself, Chef recipes. To create a class in Ruby, the traditional OOP way would look like. class User @name = nil @email =...

   RUBY,DSL,TUTORIAL     2017-03-04 09:40:34

  An alternative way to parse URL in JavaScript

Normally when we need to process URL in JavaScript, we may use the location object. Then we can use location.hostname,location.href,location.port etc to get the information we need. In this post, we will parse an URL with an alternative way. We can use an URL to create a DOM object by calling document.createElement("a"). The complete code is: function parseURL(url) { var a = document.createElement('a'); a.href = url; return { source: url, protocol: a.protocol.replace(':',''), host: a.ho...

   URL,location,parse     2014-03-03 07:05:11

  Mutli-inheritance bug between python 2.7 and 3.7

When we have run a py3.7 code under py2.x or a py2.x code under 3.x ,if a class do mutli-inheritance from 2 parent and the 2 parents also got inheritance from same parent, the different way to handle inheritance chain between python 2 and 3 will cause some running time bug: Assume we got this sample program inheritTest.py : # Purpose: Test mutli-inheritance different between python2 and 3 # Author: Yuancheng Liu # Created: 2019/05/16 class A: def getVal(self): print("cal...

   PYTHON,PYTHON 3,INHERITANCE     2019-05-16 08:33:52

  C++, Ruby and CoffeeScript complexity comparison

There are many programming languages around the world, they all designed to help programmer solve some problems, finish some tasks. These languages are often divided into different types, there are structural, object-oriented, functional, scripting languages etc. Some are easy to pick up such as Java, while some are thought to be difficult to learn such as C++. So how do we understand complexities of different programming languages?Many people agree that C++ is very complex languages, it has poi...

   Complexity, languages, C++,Ruby,CoffeeScript     2012-06-12 04:46:01

  Understand JavaScript prototype

For an front end programming language like JavaScript, if we want to understand its OOP feature, we need to understand its objects, prototype chain, execution context, closure and this keyword in deep. If you have a good understanding on these concepts, you should be confident that you can handle this language well. The inheritance in JavaScript is not class inheritance like Java, but it adopts another mechanism-- prototype inheritance. The key to prototype inheritance is the prototype chain mec...

   JavaScript, prototype, __proto__     2013-02-02 02:34:09

  How to undo git changes?

When using git for version control, there is frequent need on undoing commits due to some unexpected changes. This post will introduce how to undo changes with git command in different cases. Undo commit A common undo case is that some commit needs to be reverted as the commit contains error. In this case, the code is already committed. The command to revert the commit is git revert HEAD This command will add new a commit to the existing head to undo the previous commit. It will not change the p...

   GIT,GIT RESET,GIT REVERT,GIT CHECKOUT     2019-12-28 02:21:47

RECENT